circadian rhythms mindmap
- Created by: lucy.banks
- Created on: 09-10-21 14:11
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- Circadian Rhythms
- Biological Rhythms
- Governed by:
- Exogenous Zeitgebers
- External Changes to environment
- Endogenous Pacemakers
- The body's internal 'clock
- Exogenous Zeitgebers
- Ultradian Rhythms
- Takes less than 24 hours
- Sleep stages
- Takes less than 24 hours
- Infradian Rhythms
- Take longer than 24 hours
- Menstrual cycle
- Take longer than 24 hours
- Circadian Rhythms
- Takes only 24 hours
- Sleep-wake cycle
- Takes only 24 hours
- Governed by:
- Found in the Supra -Chiasmatic nucleus (SCN)
- Nerve findings connected to eye cross optic chaism
- SCN lies just above OC
- Nerve findings connected to eye cross optic chaism
- Light
- Primary input to this system - sets body clock to correct time
- Photo entrainment
- Primary input to this system - sets body clock to correct time
- Free-running
- Internal circadian clock
- maintains of 24-25 hours
- even in absence of external cues
- maintains of 24-25 hours
- Internal circadian clock
- Key studies
- Michele Siffre
- 6 months - texan caves & 2 months in alps cave
- deprived himself of natural light & sound with access to adequate food and drink
- Resurfaced in mid-sept after 2 months and believed it was mid-august
- His 'free - running' biological rhythm settled down to one that was just beyond the usual 24 hrs (25 hrs) - though he did continue to fall asleep & wake up on a regular cycle
- Resurfaced in mid-sept after 2 months and believed it was mid-august
- deprived himself of natural light & sound with access to adequate food and drink
- 6 months - texan caves & 2 months in alps cave
- Aschoff & Wever
- 4 weeks in a ww2 bunker
- deprived of natural light for 4 weeks
- All but 1 participant displayed circadian rhythms between 24 and 25 hours
- Natural sleep / wake cycles may be slightly stronger than 24 hrs but is entrained by exogenous zeitgebers associated with our 24 hr day
- All but 1 participant displayed circadian rhythms between 24 and 25 hours
- deprived of natural light for 4 weeks
- 4 weeks in a ww2 bunker
- Folkard et al
- 3 weeks in a cave
- 12 people, bed at 11:45 pm, wake at 7:45 am, gradually sped up their clock so a 24 hr day was actually only 22 hrs
- Only 1 participant was able to comfortably adjust to new regime
- Suggests the true existence of a strong free-running circadian rhythm that can be easily overridden by exogenous zeitgebers
- Only 1 participant was able to comfortably adjust to new regime
- 12 people, bed at 11:45 pm, wake at 7:45 am, gradually sped up their clock so a 24 hr day was actually only 22 hrs
- 3 weeks in a cave
- Michele Siffre
- Biological Rhythms
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